Abstract Body: Background Area-level socioeconomic deprivation is linked to cognitive impairment in older adults, but its impact from middle age is unclear. Evidence on the early-life deprivation effect on midlife cognitive function (CF) is limited.
Objective To investigate the effect of early-life Area Deprivation Index (ADI), on CF in middle-aged adults
Methods We assessed the association between early-life ADI and midlife CF in 1,099 subjects from the Bogalusa Heart Study (58.0% Whites, 42.0% Blacks, mean age at ADI: 12.6±5.9, mean age at CF: 48.7±5.0). Census data for 17 block-group variables were collected, including education, poverty, income, employment, and housing. Home ownership was excluded due to a factor loading below 0.3, leaving 16 variables for ADI calculation through factor analysis. The ADI was divided into quintiles, with the 1st quintile as the least deprived and 5th as most. CF was assessed through tests measuring episodic memory, working memory, attention, graphomotor information processing speed (GIPS), and global CF. Associations between ADI and CF were evaluated using a generalized estimation equation, adjusting for age at first exam, sex, race, year, and education. Interaction terms of race and education with ADI quintiles were tested.
Results The independent t-test showed Blacks had a higher ADI than Whites, indicating greater deprivation (0.81±0.58 vs. –0.60±0.80, p<0.001). Global CF decreased in the 5th ADI quintile compared to the 1st (β=–0.002 standardized unit [SE: 0.001], p=0.001), with a downward trend across quintiles (p=0.002). Episodic memory, working memory, attention, and GIPS also decreased as the quintile of ADI increased (p<0.001). Interaction terms with education showed significant negative effect on CF among high school graduates (1^st vs. 4^th quintile: β=–0.004 [SE: 0.002]), and those with education beyond high school (1^st vs. 5^th quintile: β=–0.004 [SE: 0.002]), but not among less than high school (1^st vs. 5^th quintile: β=–0.003 [SE: 0.001]; p for interaction: 0.011). Interactions between ADI quintiles and race were not significant.
Conclusion Higher early-life ADI was associated with lower midlife CF, with a decline observed in CF in the most deprived quintile, although effect sizes were modest. The strongest negative impact was observed among those with high school education or higher.
Keywords area deprivation index; cognition; middle-aged adults